In a three-phase power system, the three-phase power may be considered as consisting of three sets of single-phase power, in which a difference among the three sets of single-phase power is 120°. The three-phase power can be simultaneously provides to a plurality of three-phase load apparatuses and/or a plurality of single-phase load apparatuses. Even though the three-phase power can be simultaneously provided to the load apparatuses, factors, such as the single-phase load apparatuses using the power in the same phase among the three-phase power, the single-phase load apparatuses having different power consumption from one another, or the single-phase load apparatus having different turned-on periods, would lead the three sets of single-phase power in consuming different amounts of electricity. In the scenario that the three sets of single-phase power consumes different amounts of electricity, a power generating terminal (e.g., a utility power, a commercial power, or a supply mains) has to conform to the highest load of each single-phase power. In any way, the load unbalance status of the three set of the three-phase power would lead to energy loss and cause risks, such as an over large current and power trip-off of neutral lines of a user end.